Muhlenbergia fastigiata (J. Presl) Henrard

Dense mat-forming perennials with scaly rhizomes, the acute scales 4.5−8.1 (−10) mm long, the rhizomes 1−2 (−2.5) mm in diameter. Culms 2−8 (−11) cm long, mostly erect, 2−3 (4) mm diameter below; internodes 1−10 mm long, compressed. Leaf sheaths 3−6 (−10) mm long, distichous, overlapping, margins hyaline; ligules 6−1.4 mm long, membranous, decurrent, apex acute to obtuse; blades 2.5−8.5 mm long, 0.6−1.1 mm wide, involute, arcuate, glabrous to finely papillose, margins scabrous, apex navicular, often pungent. Panicles 1−2 cm long, 1−5 mm wide, contracted, narrow, usually exserted with 3−9 nodes; primary branches 0.4−1 cm long, ascending, solitary at a node; rachis papillose-roughened just below the spikelets. Spikelets (1.8−-) 2−2.5 mm long, plumbeous; glumes (0.8−) 1−1.6 mm long,about ½ as long as the floret, subequal, 1-veined, rarely 2-veined, apex acute to obtuse; lemmas (1.7−) 1.9−2.4 mm long, 3-veined, glabrous, plumbeous, apex acute, mucronate, the mucros less than 0.3 mm long; paleas (1.6−) 1.8−2.4 mm long, 2-veined, glabrous; anthers 1−1.7 mm long, yellow or purple. Caryopses 1−1.3 mm long, about 0.4 mm wide, ellipsoid, dark brown.

Muhlenbergiafastigiata is found in South America in the Andean highlands of Argentina, Bolivia, Chile, Colombia, and Peru (Morden 1985; Morden and Hatch 1996).